Astronaut performance jeopardised by sleep deprivation

Ever since the Apollo 11 headed to the Moon in late 1969,
astronauts have complained of sleep deprivation. Now a study has shed light on the extent of the sleep deprivation
and fatigue suffered by those who travel into space.

In accordance with official Nasa flight schedules, astronauts
are ordered to get 8.5 hours of sleep every night. But after
tracking the sleep patterns of 85 crew members aboard the
International Space Station (ISS) and space shuttles, researchers
have discovered that astronauts on shuttle missions sleep for under
six hours per night on average and just over six on ISS
missions.

Crew members on modern space missions sleep in quiet, darkened
chambers and three quarters of astronauts take sedatives -- yet the
problem still prevails. It was not only during sleep that
astronauts failed to get to get the required amount of sleep,
however. In the three-month pre-flight training period, sleep was
also found to be significantly disturbed. During this time crew
began to build up a long-term sleep deficiency, averaging less than
6.5 hours while in training.

The number of astronauts taking sleep medication has also been
highlighted as a particular concern, after the study discovered
that three quarters of ISS crew take sleep medication at least once
during their stay and that 78 percent of shuttle crew members used
medication on more than half of their nights in space.

"The ability for a crew member to optimally perform if awakened
from sleep by an emergency alarm may be jeopardised by the use of
sleep-promoting pharmaceuticals," warned Laura K Barger from Brigham and Women's Hospital, who is
lead study author. Taking sedatives and hypnotics has also widely
been found to impair performance and physical activities, which is
why many such medications carry warnings against operating heavy
machinery or vehicles after ingestion.

The ten-year study has seen more than 4,000 nights of
astronauts' sleep on Earth and over 4,200 nights of sleep in space
be recorded, and has concluded that more action needs to be taken
to help optimise performance of astronauts.

"Because chronic sleep loss leads to performance decrements, our
findings emphasise the need for development of effective
countermeasures to promote sleep," write the authors in the study's
abstract.

Sleep deprivation has been found to be highly detrimental to an
astronaut's performance both during training and space flight.
Closer to Earth, around 15-20
percent of fatal airline crashes caused by human error are
thought to be a direct result of pilot fatigue. There is no
consensus yet on what countermeasures should be implemented, but
they could include scheduling modifications and the teaching of
behavioural strategies.